Full Idea
Supervenience is a necessary condition for physicalism, but it is not sufficient. Epiphenomenalism rules out mental variation without physical variation, but says mental properties are quite distinct from physical properties.
Gist of Idea
Epiphenomenalism is supervenience without physicalism
Source
David Papineau (Philosophical Naturalism [1993], 1.2)
Book Reference
Papineau,David: 'Philosophical Naturalism' [Blackwell 1993], p.11
A Reaction
I take full epiphenomenalism about mind to be incoherent, and not worth even mentioning (see Idea 7379). Papineau seems to be thinking of so-called property dualism (which may also be incoherent!).
Related Idea
Idea 7379 If an epiphenomenon has no physical effects, it has to be undetectable [Dennett]